1. Field of the Invention
This document relates to a liquid crystal display.
2. Discussion of the Related Art
An active matrix driving type liquid crystal display displays moving pictures by using a thin film transistor (hereinafter, “TFT”) as a switching element. Since such LCDs can be made smaller than cathode ray tubes, they are rapidly replacing the cathode ray tubes in television sets, as well as in displays of mobile information devices, office machines, computers, etc.
Liquid crystal cells of a liquid crystal display picture images by changing transmittance according to a potential difference between a data voltage supplied to a pixel electrode and a common voltage supplied to a common electrode. The liquid crystal display is generally driven in an inversion scheme in which the polarity of a data voltage applied to liquid crystal is periodically inverted in order to prevent deterioration of the liquid crystal. When the liquid crystal display is driven in the inversion scheme, the picture quality of the liquid crystal display may decrease according to a correlation between the polarity of a data voltage to be charged in the liquid crystal cells and the data voltage. This is because either one of the positive and negative polarities of the data voltages charged in the liquid crystal cells becomes a dominant polarity according to the data voltages charged in the liquid crystal cells without balance between the positive and negative polarities, and therefore the common voltage applied to the common electrode is shifted. When the common voltage is shifted, the reference potential of the liquid crystal cells is fluctuated. Thus, the observer can sense flicker or smear in an image displayed on the liquid crystal display.